As Orlove noted, barter may occur in commercial economies, usually during periods of monetary crisis. During such a crisis, currency may be in short supply, or highly devalued through hyperinflation. In such cases, money ceases to be the universal medium of exchange or standard of value. Money may be in such short supply that it becomes an item of barter itself rather than the means of exchange. Barter may also occur when people cannot afford to keep money (as when hyperinflation quickly devalues it).[15]
For instance, each time Apple releases a new version of the iPhone, the second-hand market for older versions of the iPhone enjoys a flurry of activity. However, you do have to be as careful with the barter of used goods as you would be with the purchase of used goods. Be sure everything is in working order and shows no signs of significant damage.
^ Homenatge A Catalunya II (Motion Picture). Spain, Catalonia: IN3, Universita Oberta de Catalunya, Creative Commons Licence. 2010. Retrieved 2011-01-15. A documentary, a research, a story of stories about the construction of a sustainable, solidarity economics and decentralized weaving nets that overcome the individualization and the hierarchical division of the work, 2011.
No academics I talked to were aware of any evidence that barter was actually the precursor to money, despite the story’s prevalence in economics textbooks and the public’s consciousness. Some argue that no one ever believed barter was real to begin with—the idea was a crude model used to simplify the context of modern economic systems, not a real theory about past ones.

During economic downturns, when there is a keenly felt shortage of jobs and cash, people have historically adopted barter systems. The world’s most established bartering-style system is Switzerland’s wir: the German word for “we” as well as the abbreviation of Wirtschaftsring, which translates loosely to “economic circle.” In 1934, the economy in Switzerland had tanked—as it had in much of the world. Two businessmen who were facing bankruptcy, Paul Enz and Werner Zimmermann, gathered 15 of their associates in Zurich and hashed out a solution: a mutual credit system.